electronics

The type of voltage regulator that I used for the first Lawnbott Live camera was only rated for 8V, so I needed to get a 12V one. I bought the only one I found at Radio Shack. However, it didn’t seem to work for the new camera setup (I’ll write about what the setup is once it is working). I suspected the 1 amp limit on the regulator might be the problem. I only paid for one AC adapter with the new camera so I had to scrounge around the house looking for two more in order to test things out without Betsie’s battery. Luckily 12V adapters are very common (got one from the old Linksys router and another from … something…). I plugged everything into the wall and lo-and-behold it worked perfectly. Nice picture! I went back to using battery power and the transmitter barely made it to the receiver over a 3 foot distance. Hmmm…. The transmitter needs more power.

I realized that my scrounged adapters came in different two different amperage values, one 500mA and one 1A. I knew my voltage regulator was rated for 1A, and had thought that might be the problem (if you can’t get enough current then you can’t get enough power as Power = Voltage * Current). I switched the transmitter to the 1A AC adapter and powered the camera from Betsie and everything worked great again.

This is when I started researching voltage regulators and came across switching regulators. Similar concept, looks about the same from outside the IC, but inside it’s all different. How it’s different goes beyond this Mech. E’s interest/experience level, but the end result is that it’s a lot more efficient. In a linear voltage regulator the voltage dropped is lost as heat. This really only works when you’re at low powers or small voltage drops. No, I didn’t do the calculation to figure out how much I’m wasting, but I did burn my fingers last time so I know there’s a lot of heat being wasted. The switching regulator is rated for 80% efficiency. Since I know I need more power, it seemed like a good way to go.

Here’s the part I ordered: http://octopart.com/info/Diodes+Inc./AP1512A-12K5L-13

It arrived today, so I might get a chance to put things together.

I’m still operating without a soldering iron and without my own voltmeter so I probably won’t get anything finished tonight. I need to fix this!